安卓写文件

package pw.pw11.writetext;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.EditText;


public class MainActivity extends AppCompatActivity {
    private EditText edit;
    private String path;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        edit = (EditText) findViewById(R.id.editText);
        path = getInnerSDCardPath();
    }
    @Override
    protected void onDestroy() {
        super.onDestroy();
        String content = edit.getText().toString();
        WriteText(path,"test.txt",content,false);
    }
    public String getInnerSDCardPath() {
        return android.os.Environment.getExternalStorageDirectory().getPath();
    }
    public void WriteText(String path,String filename,String content,boolean append){
        java.io.FileOutputStream fs=null;
        try {
            java.io.File file = new java.io.File(path+"/"+filename);
            fs = new java.io.FileOutputStream(file,append);
            fs.write(content.getBytes());
        } catch (java.io.IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (fs != null) {
                    fs.close();
                }
            } catch (java.io.IOException e) {
                e.printStackTrace();
            }
        }
    }
}